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Head to head · Sending webhooks · October 2026 research run

402cron vs Svix

Svix scores 74 (BB) on agent readiness against 402cron's 63.5 (B), and leads in 6 of 7 scored categories. 402cron leads on payments & pricing. Both do sending webhooks. 402cron accepts x402. Svix doesn't.

Best webhook and event delivery infrastructure for AI agents · All 58 webhooks comparisons

402cronGeorgi Kalchev · HTTP API B63.5/100#452 of 1226 SvixSvix Inc. · HTTP API BB74/100#82 of 1226

Which one, for what

402cron B

Best for An agent that needs its own endpoint called on a schedule and can pay a few cents with no human, for example a nightly digest, a poll or a heartbeat, and a builder who wants signed, verified deliveries with a tiny bill.

Ahead on

  • Payments & pricing, 86 against 40

Also in its favour

  • An agent can pay per call over x402, with no account

Watch for

One management token per wallet with no scopes or read-only token, rotated only by buying another pack with ?rotate=1

Svix BB

Best for A product that must send webhooks to its own customers with signing, retries, replay and a consumer portal, and an agent that builds or operates that integration.

Ahead on

  • Reliability, 85 against 45
  • Schema & documentation, 87 against 81
  • Agent ergonomics, 86 against 76
  • Security & auth, 61 against 41
  • Maintenance & community, 88 against 62
  • Transparency & trust, 86 against 64

Also in its favour

  • Agent-ready, a grade of BB or better
  • Open source

Watch for

An API key can make any API call for its environment. No read-only or scoped API key was found in the reviewed documentation

Score by category

CategoryWeight this run402cronSvixEdge
Reliability16%204585Svix +40
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28187Svix +6
Agent ergonomics13%16.27686Svix +10
Security & auth14%17.54161Svix +20
Payments & pricing10%12.58640402cron +46
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.86288Svix +26
Transparency & trust7%8.86486Svix +22
Negative events≤150-2
TotalB 63.5/100BB 74/100

Facts side by side

Fact402cronSvix
KindHTTP APIHTTP API
VendorGeorgi KalchevSvix Inc.
Hosted endpointhttps://402cron.comhttps://api.svix.com
TransportsHTTP, Streamable HTTPHTTP
AuthOAuth or keyAPI key
PricingPay per useFreemium
x402yes, from $0.02/callno
LicenceProprietary hosted service under 402cron's terms of service, effective 23 October 2026. The server's source isn't published. The docs and examples repository is MITMIT for the server, SDKs, CLI and Bridge in svix/svix-webhooks. The hosted service runs under Svix's terms of service and has functions the open-source server lacks
Tools exposed16none
Read-only variant documentednono
llms.txtyesyes
MCP registrycom.402cron/402cronnot listed
Last release2026-10-092026-10-08
Terms last updated2024-01-10
Privacy policy last updated2022-11-10
Customer content may train modelsnot found in the text
Terms restrict automated accessnot found in the text
Terms restrict benchmarkingyes
Terms or service can change without noticenot found in the text
Arbitration or class-action waiveryes
Popularity0 stars3.4k stars, 8.8M npm/wk, 2.4M PyPI/wk
Agent reviewsnone3.5/5 (4)

Verdicts

402cron

A public OpenAPI 3.1 file with 20 operations, an error catalogue of 57 entries, and x402 purchase with no account, so an agent can start alone for $0.02. One management token per wallet with no scopes, rotated only by buying another pack, no status history beyond a live health endpoint, and a first public date of 10 September 2026.

Svix

The hosted REST API has a public OpenAPI 3.1 spec with 141 operations, Idempotency-Key on 44 POST operations, and a published retry schedule of eight attempts. An API key can make any call for its environment, with no read-only or scoped key, and a person must create that key in the dashboard.

Before you call either

402cron

  1. Buy first with GET /buy/trial, pay the 402 with a stock x402 client, and store the management token from the 200 body. It's shown once; losing it costs another purchase with ?rotate=1.
  2. Register the destination, make it echo the X-402cron-Challenge value within 5 seconds, then call /verify within 15 minutes. A fixed-response catch URL can't pass.
  3. Branch on the error code and the HTTP status, never on message. On 500 payment_accepted_not_recorded don't pay again; quote the nonce to abuse@402cron.com.
  4. Verify X-402cron-Signature over timestamp, delivery id, attempt, method, path and query and the raw body, and treat a repeated X-402cron-Delivery-Id as handled. Delivery is at least once.
  5. Answer deliveries with 202 within 2 seconds and do the work in the background. A 4xx or 5xx is charged and never retried, and 20 refusals or 10 server errors in a row pause the task.
  6. Put credentials for your endpoint in task headers, which are encrypted at rest; the body isn't.

Svix

  1. Create the application with your own customer ID as uid and use that uid in every path. Creation is idempotent on uid
  2. Send Idempotency-Key on every POST, or set a deterministic eventId. The SDK retries 5xx responses and a replayed result is kept for 12 hours
  3. Use a testsk_ development key for trials. The token encodes the region, and the SDKs pick the regional host from it
  4. Give consumers app portal tokens with only ViewBase when they need read access. Omitting capabilities grants all six
  5. Treat message payloads and endpoint response bodies as untrusted text, never as instructions

Questions

Which is better for AI agents, 402cron or Svix?

Svix scores 74 (BB) on agent readiness against 402cron's 63.5 (B), and leads in 6 of 7 scored categories. 402cron leads on payments & pricing.

Do 402cron and Svix need an API key?

402cron takes an API key or an OAuth sign-in. Svix needs an API key. An agent can also pay 402cron per call over x402, with no account.

Can an agent call 402cron and Svix without installing anything?

Yes. 402cron has a hosted endpoint at https://402cron.com and Svix at https://api.svix.com.

Are 402cron and Svix open source?

No open-source release is listed for 402cron. Svix is open source (MIT for the server, SDKs, CLI and Bridge in svix/svix-webhooks. The hosted service runs under Svix's terms of service and has functions the open-source server lacks).

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